Discharge valve



Oct. 17, 1933. J, c U N ETAL 1,931,017

DISCHARGE VALVE Filed Jan. 19, 1931 2 Sheets-Sheet l hf/EU/EFE Oct. 17, 1933. c BUCHANAN r AYL 1,931,017

DI SCHARGE VALVE Filed Jan. 19, 1931 2 sheets-sheep 2 Patented .Oct. 17, 1933 UNITED STATES PATENT OFFICE .DISCHARGE VALVE Application January 19, 1931. Serial No. 509,612

This invention relates to improvements in discharge valves for compressors and has particular reference to improving the quietness and efficiency of operation of flapper valves for rotary compressor-s wherein the compressor volume is normally completely swept by the rotor.

Flapper valves, as the name implies, have heretofore been positioned over a port or valve seat by being pinned down at one end, the other end crease the impact on a valve of the type mentioned by providing a clearance space betweenthe compressor cylinder and the valve port to permit the more gradual escape of entrapped lubricant or 26 7 other liquid.

It is another object of this invention to provide an improved and simplified compressor discharge valve arrangement of the type described which will be economical to manufacture and easy to assemble and service.

Other and further important objects ofthis invention will be apparent from the disclosures in the specification and the accompanying drawings.

This invention (in a preferred form) is illus trated in the drawings and hereinafter more fully described.

On the drawings:

Figure 1 is a central longitudinal section, partly in elevation, of a rotary compressor chosen to illustrate an application of the discharge valve of this invention.

Figure 2 is an elevational view of the compressor proper with the front housing or lubricant reservoir removed.

Figure 3 is an enlarged fragmentary. view of a portion of Figure 2 with the discharge valve housing removed, to show the relation of the valve port to the partition blade.

Figure 4 is an enlarged fragmentary section on the line IV-IV of Figure 1.

Figure 5 is an enlarged section through the valve housing, on the line VV of Figure 2.

As shown on the drawings:

The compressor chosen for illustrative purposes is of a rotary type and in the form illustrated is It is a further object of this invention to de- 1 primarily intended to be belt driven as. a partof domestic refrigeration apparatus wherein quietness and smoothness of operation is an essential quality. The exact type of compressor is immaterial to the present invention, which relates to 0 a discharge or check valve that operates with the minimum of noise compatible with the maximum efficiency in operation.

The illustrated compressor structure comprises a body 11 having a central cylindrical bore 5 12 with outstanding end flanges 13-, the faces of which are finished parallel to each other and at right angles to the cylindrical bore, the perimeter of the flanges being finished concentric with the bore to provide locating shoulders for end closures containing bearings for a compressor shaft 14. A back closure 15 is shown in elevation in Figure l, in. which a front closure 16 is formed, as a lubricant reservoir or housing containing a stufiing box 17 and shaft seal 18 as well as a shaft bearing 19 concentric with thecylindrical bore. The shaft carries an eccentric 20 within the cylindrical bore, on which eccentric is mounted a rotor or sleeve 21 which is so proportioned asto just clear the cylinder wall at the position of maximum eccentricity of the eccentric. This sleeve floats on the eccentric and is therefore free to roll within the cylindrical bore as it is oscillated thereon by the rotation of the shaft and eccentric. In practice it is ap- 5 proximately stationary relative to the part generating the greatest friction, which is usually the partition blade 22. This blade is slidably mounted in a slot 23 in the cylinder which slot terminates in a drilled hole 24 which admits lubricant back of the blade. A spring 25 is so positioned in a boss 26 as to act against the blade to supplement the pressure of the lubricant thereon to cause the blade to maintain contact with the sleeve or rotor 21.

End seals or covers 2'7 are applied to each flange 13 of the body in the form of annular plates which make sealing contact with the rotor sleeve 21 while having ample clearance from the shaft itself. The and seal on the discharge side is formed with a discharge port 28 over which a discharge valve housing 29 is applied, the housing having an apertured boss 30 into which a tube 31 is sealed which tube leads the discharge into the upper part of the reservoir 16 above the lubricant level therein. The port 28 is on the discharge side of the partition blade, while a suction passage 32 opens into the compression space on the opposite side of the blade.

The d scharge port 28 in the end cover opens 11 directly into the cylinder or compression space adjacent the partition blade, as indicated in Figure 3 so that at the end of the compression period the rotor sleeve substantially covers the port. The cylindrical bore is therefore chamfered adjacent the blade slot, as indicated by the numeral 33, and the port 28 has a sideways enlargement 34 over the chamier to permit a continued discharge from the clearance space formed by the chamfer 33 when the rotor sleeve reaches its position of maximum eccentricity towards the blade, and hence blocks'the normal discharge port.

The outer face of the end cover is chamfered around the edges of the port 28 as indicated at 35 in Figure 5 in order to increase the available valve surface relative to the port size. This chamfer 35 is provided instead of an enlarged port as it has been found by experiment that in-'- creasing the port area, or volume as by increasing the cover thickness, is not equivalent to providing the same volume as a clearance space in the chamfer 33 in direct connection with the cylindrical bore across its full width. In other words, the eilective clearance should be open directly to the cylinder, rather than in a passage beyond the point of initial delivery from the compressor, in order to be eflective in reduc the noise in operation. I

The port 28 is covered by a centrally disposed flap valve 36 aligned therewith, one end of the valve being held down by a screw 37 or the like, while the other end thereof is held down by a ball 38 backed by a spring 39, both in a recess 40 in the valve housing. The outlet passage 41 through the valve housing is directly over the center of both the flap valve and the port 28 so that when the valve opens it has to buckle in the center, as indicated in dotted lines in Figure 5, one end sliding back andforth under the ball which holds this end against the surface of the end closure or cover.

The operation of the rotary compressor itself is well known and does not require extended description as the sleeve is carried around in the cylinder in a clockwise directionsothat the compression space revolves likewise, decreasing in volume above the partition blade in Figure 4 as it increases in volume on its suction cycle below the blade. The compressed gas is thus swept ahead of the rotor sleeve into the chamfer 33 and thence through the port 28 past the buckled valve 36 into the valve housing and out through the discharge tube 31. The discharge valve is normally seated by the back pressure acting through the tube 31, except during short intervals when the compressor develops suflicient pressure to unseat the valve, which then buckles in the center to allow escape of the compressed gas past both edges of the valve. The ball 38 and spring 39 hold the free end of the valve down while permitting the necessary back and forth movement. The clearance space adjacent the compressor cylinder bore is an important factor in reducing the noise of operation as it reduces wire drawing and softens the impact of entrained liquids on the valve.

It will thus be seen that we have invented an improved valve for rotary compressors having features of increased quietness and reliability in operation.

We are aware thatmany changes may be made and numerous details of construction may be varied through a wide range without departing from the principles of this invention, and we, therefore, do not purpose limiting the patent granted hereon otherwise than necessitated by the prior art.

We claim:

1. In a rotary compressor of the type having a cylinder and a piston, one of which is rotatabierelative v to the other, and a partition blade slidable in a slot in the stationary member, a clearance space extending across the width of the. compressor and formed in the stationary member immediately contiguous to the compression side of the partition blade, a discharge port having a valve seat in direct continuous communication with said clearance space, an elongated flap valve strip the center portion of which over- 3105 lies said discharge port and valve seat,'means for rigidly mounting the flap'valve strip at one end, and a resilient hold down mounting for the other end outside the limits of the valve seat whereby the valve strip is free to buckle up in the center over the valve seat while the resiliently held endthereof is constrained to slide back and forth to provide friction outside the valve seat location for cushioning the valve movements.

2. Ina rotary compressorof the type having all cylinder and a piston, one of which is rotatable relative to the other, and a partition blade slidable in a slot in the stationary member, a clearance space formed in the stationary member immediately contiguous to the compression side of 1 0 the partition blade, a discharge port having a valve seat in direct continuous communication with said clearance space, an elongated flap valve strip the center portion of which overlies said discharge port and valve seat, means for rigidly 2 mounting the flap valve strip at one end, and a resilient hold down mounting for the other end outside the limits of the valve seat whereby the valve strip is free to buckle up in the center over the 'valve seat while the resiliently held end thereof is constrained to slide back and forth to provide friction outside the valve seat location for cushioning the valve movements.

' JOHN C. BUCHANAN.

EARL F. HUBACKER. 

